The present inventive concept herein relates to supply regulated voltage controlled oscillators and phase locked loops using the same, and more particularly, to a supply regulated voltage controlled oscillator including an active loop filter and a phase locked loop using the same.
A voltage controlled oscillator generates an oscillating signal corresponding to a voltage output from a loop filter of a phase locked loop and provides the generated oscillating signal to the outside. The phase locked loop (PLL) receives a reference frequency signal from the outside and receives a frequency signal which is generated from a voltage controlled oscillator autonomously having a variable frequency through a negative feedback loop to control the voltage controlled oscillator so that a signal is output which has a minimum phase difference between the two received frequency signals while having a same frequency. The phase locked loop is widely used in a communication system or digital equipment that performs generation or restoration of a clock signal, a frequency modulation, a frequency demodulation, a frequency synthesis and a frequency multiplication.